NOTE: You can setup build system quickly with docker by running scripts in ./scripts, or you can follow the below steps for manual setup on your machine.

Setup sbuild

Install sbuild

On Debian Jessie, sbuild needs be installed from jessie-backports because current sbuild of jessie does not work with gnupg2 of Buster (Bug #827315)

$ echo "deb http://ftp.debian.org/debian jessie-backports main" | sudo tee -a /etc/apt/sources.list
$ sudo apt-get update
$ sudo apt-get -t jessie-backports install sbuild

Configure user

$ sudo mkdir /root/.gnupg # To work around #792100; not needed post-Jessie
$ sudo sbuild-update --keygen # Not needed since sbuild 0.67.0 (postJessie, see #801798)
$ sudo sbuild-adduser $LOGNAME

logout and re-login or use newgrp sbuild in your current shell

Create sbuild chroot

$ sudo sbuild-createchroot --include=debhelper unstable ./chroot-sbuild http://ftp.debian.org/debian

You should change the URL to your Debian fastest mirror.

Update build script

Check name of chroot which has just been created, then you can use it to run cross-build:

$ schroot -l | grep sbuild
chroot:unstable-amd64-sbuild

## You can try running sbuild with command
$ sbuild --host=armhf -d unstable-amd64-sbuild <package>.dsc

Update command sbuild in sbuild-loop.sh with your chroot.

Setup reprepro

"reprepro is a tool to manage a repository of Debian packages (.deb, .udeb, .dsc, ...)."

$ sudo apt-get install reprepro

Config for reprepro has been created in repo/conf. You should change the URL in ./repo/conf/updates to your Debian fastest mirror. It will save time on fetching.

In repo/conf/distributions, local repo is defined with codename unstable-cross. You can update source for local repo with command:

$ reprepro -b ./repo update unstable-cross

Packages, which we want to fetch, are listed in repo/conf/filters/pkglist

Run

Set cron job to fetch source code and run sbuild weekly. sbuild-loop.sh only builds newest packages (base on repo/logs/logfile)

$ crontab -e
0 0 * * 6 cd <this dir> && reprepro -b ./repo update unstable-cross && ./sbuild-loop.sh

References

https://wiki.debian.org/sbuild

https://wiki.debian.org/Schroot

https://wiki.debian.org/CrossCompiling

https://wiki.linaro.org/Platform/DevPlatform/CrossBuildd